Aerodynamics and Design for Ultra-Low Reynolds Number Flight

Chapter 8
not been determined whether this is an issue of gridding or numerics, or if this is
supported by the flow physics. If it is a real phenomena of ultra-low Reynolds number
operation, it suggests a simple modification to the current semi-infinite wake model that
would strongly influence inflow velocities.
Additional improvements in the performance of the rapid analysis and design method
could be readily achieved by integrating the current torsional deflection model directly
into the design and analysis process. In the very least, this would eliminate the tedious
manual iteration on deflection and aerodynamic loading carried out in Chapter 6.
If performance constraints warranted it, considerably more effort could be applied to
move beyond this level of refinement and to fully account for three-dimensional effects
in design. The rapid analysis and design method does not presume to achieve the fidelity
of three-dimensional computational Navier-Stokes solutions, and shape optimization
within 3-D Navier-Stokes computations has become more common. Such an approach
would be currently be computationally expensive, but advances in computational
technology and reductions in the financial cost of computing resources are rapidly
making this a viable solution. However, it is not yet clear if the costs and complexity are
warranted.
A novel approach to experimental testing of ultra-low Reynolds number rotors would be
to make scale models, but in the opposite direction than is typical, larger not smaller.
Reynolds number scaling would simply dictate slower rotational speeds. Increased size
would simplify manufacturing, and facilitate maintaining and assessing geometric
accuracy, and potentially improve the experimental accuracy by increasing the
magnitude of the global metrics. Larger rotors would also open the possibility of
experimental visualization, providing a comparison point to the details of the
OVERFLOW-D solutions.
In a more supporting role, development of the rotorcraft prototypes would also facilitate
new avenues of research. They potentially represent small, inexpensive, and highly
maneuverable test-beds for research into distributed systems, collective intelligence,
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